find_path(PNG_INCLUDE_DIR png.h
  "{INCLUDE}"
  "{LIB_DIR}/include"
)

find_library(PNG_LIBRARY NAMES libpng16 PATHS
      "{LIB}"
      "{LIB_DIR}/lib"
      "{LIB_DIR}/lib64"
    )

if (PNG_INCLUDE_DIR AND PNG_LIBRARY)
  set(PNG_FOUND TRUE)
endif()
